Metallic Granite

[toppshops]

Hey guys, I just stumbled onto this site and found that it had quite a lot of useful information and a a lot of people on here seam to know a lot about granite fabrication, so I've got a question.

We're currently working on a metallic granite job.  It's one of those stones with some very soft spots and some very hard spots.  We plan on rodding the tops in all the weak spots but I was wondering if anyone had any tips on how to polish this stone without getting a lot of waves in the edge.  We tested a piece to see how hard it would be to put a 1/4" radius on the top and the result was horrid.  The top edge of the round over was uneven on the length of the piece.  We're also a little worried because the undermount sink has to be pretty much exact from our template, but because of the different hardness of the material, polishing may cause the cutout to differ from the template... Any help would be greatly appreciated.

[Mark D.]

What stone is this you are dealing with?
What pads are you using for your polishing?

Mark

[toppshops]

The color is called metallic.  If you do a google search for metallic granite, i'm pretty sure the first website is a picture of the stone.  We're using 4" wet pads (I forget what brand, we've been switching pads a lot, but I think they might be viper pads).  The problem with this stone is that the soft spots are so soft you can almost rub them away like sand.  So if you have any suggestions on how to keep this from happening during polishing, it would help greatly.

[Mark D.]

I am not sure I understand you, but if you mean that when you are edge polishing some of the stone is popping out then it is probably mica, so you really can't do much. just polish it and the address the divots if necessary.

Mark

[Stone Dude]

you need to use a rigid pad, not a flexible one. there is a stone called Iron Red, that has a crapload of iron in it. you can stick magnets to it. you have to cut 2cm in two passes and it wreaks havocs on blades. a lot of guys replace the blade after cutting a kitchen.

DeFusco sells Alpha Twist Touch pads. these will work for everything except inside corners (like the sink) these are what you should use through 500 grit. then switch the to the "shine" pads @400-3000 grit, which you can also find @ DeFusco. the rigid pads with drastically reduce the wave. dont forget to buy the backer that goes with them.

[dafranca]

toppshops,

First thing to do is identify the stone. Metallic isn't a granite. It is a shale stone. The quarry owner is Nova Aurora in Brazil, it cost here(Brazil) about $23.00 in 3cm. Now there are similar stones here for about $11.00.

Back to the edge... since this is a Shale Stone. It is impossible to do a good edge without resin it. Shale Stones uses 10x more resin them a "true granite".
This is now to get the edge on it:

1) Cut like the template
2) Make the edge(make it honed), don't use all the pads, only half way.
3) Get same resin on it, I would recommend a fine Tenax resin for 36hours.
4) Hit up the resin with fire to get the air out of it and make the resin penetrate. the resin may get suck up, so apply more resin and hit with fire again.
5) Let it cement on it for 2-3(3 days in winter 2 days in summer)
6) Now you are good to finish up the edge.